Drawing-board.



PATENTED AUG. 13, 1907.

o. MQKENZIE. DRAWING BOARD.

APPLIOATION FILED NOV. 17r1906.

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UNITED STATES PATENT OFFICE.

WILLIAM G. MCKENZIE, OF FLATBUSH, NEW YORK, ASSIGNOR OF ONE-FOURTH TO FRANK M. LAUDGRAFF, OF BROOKLYN, NEW YORK, AND ONE-FOURTH TO WILLIAM F. OETJEN, OF

FLATBUSI-I, NEW YORK.

DRAWING-BOARD.

Specification of Letters Patent.

Patented Aug. 13, 1907.

To all whom it may concern:

Be it known that 1, WILLIAM C. MCKENZIE, a citizen of the United States, residing at Flatbush, in the county of Kings and State of New York, have invented a new and useful Improvement in Drawing-Boards, of which the following is a specification.

This invention relates to drawing boards such as are used by draftsmen and artists in preparing their drawings. In the practical use of such drawing boards, at the points where the thumb-tacks are inserted the wood becomes punctured and honeycombed, so that in a board which has had considerable use the hold of the wood on the thumb-tack becomes much impaired. On this account, boards which are still apparently useful in other respects must be discarded.

The object of this invention is to produce a drawing board having means for insuring that the thumbtacks will always be firmly seated in the board.

The invention consists in the construction and combination of parts to be more fully described hereafter, and more fully set forth in the claims In the drawing, which fully illustrates my invention, Figure 1 is a perspective of a drawing board constructed according to my invention. Fig. 2 is a vertical transverse section taken through the drawing board, substantially through the line 22 of Fig. 1. A portion of this view is represented as broken away, and the view is upon an enlarged scale. Fig. 3 is a longitudinal section taken on the line 33 of Fig. 1, and this view is broken away and is upon an enlarged scale. Fig. 4 is a reverse plan of a corner of the drawing board. Fig. 5 is a plan of a corner of the drawing board showing the parts with a portion of the body of the drawing board removed. Fig. 6 is a plan of a slip which I set in the face of the board at the points where the thumb-tacks areapplied.

Referring more particularly to the parts, 1 represents the body of the board, which is of the usual rectangular form. On the under side of this body, at the ends thereof, and disposed transversely of the grain of the wood, 1 provide cleats, 2. These cleats are preferably attached to the board body, 1, by setting the ends of the boards in rabbets or grooves, 3. These cleats preferably extend the full width of the board, so that their extremities are flush with the side edges thereof, as will be readily understood. At the corners the board body, 1, is formed with recesses or seats, 4, which are of quadrilateral form, as shown, and presenting converging side edges, 5 and 6, which project inwardly toward the cen ter of the board, as shown. These side edges, 5 and 6, are undercut, as indicated, so as to form retaining grooves 7, for a purpose which will appear more fully hereafter. These recesses, 4, receive slips, 8, which are formed so as to fit the recesses. One of these slips is very clearly illustrated in Fig. 6. They present converging edges provided with tongues, 5), projecting latthat the recesses, 4, constitute seats for the slips, and it will also be readily seen that the tongues, 9, hold the slips in the face of the board, so that the slips can only be removed by sliding them outwardly, 0., by reversing the movement by which they were inserted' As shown Very clearly in Figs. 2 and 3, the outer faces of the slips are flush with the outer face of the board body.

I provide means for locking the slips in position, so that they cannot become accidentally removed. For this purpose, each of the cleats, 2, is provided with a longitudinal bore, 10, as indicated in Figs. 4 and 5, and in this bore there is received a rotatable shaft, 11. These bores extend through the cleats to a point near the end opposite which they are inserted, as indicated in Fig. 2. At the entrance to each bore a counter bore is formed, as shown in Fig. 2, to receive a conical head, 12, which is formed upon the shaft. Each ofthese heads, 12, is provided with a notch, 13, which enables the shaft to be rotated by means of a screw-driver. It will be observed from inspection of Fig. 1 that these shafts extend under the slips, 8. At points under the slips the cleats are provided with openings, 14, as indicated in Figs. 2 and 3, and in these openings locking 1 collars, 15, are rigidly attached. The bodies of these collars are of substantially cylindrical form, and each collar is provided with a projection or toe, 16, and each of these toes is provided with a beveled face, 17, as indicated most clearly in Fig. 5. At the sides the collars, 15, are provided with teeth, 18, on their under sides and these teeth are engaged by keepers, 19, said keepers having the form of leaf springs, the shanks of which are attached in recesses, 20, at the sides of the openings, 14, as indicated most clearly in Fig. 3. On the under side of each of the slips, 8, recess, 21, is produced, and these recesses have substantially the form shown in Fig. 6. Each recess presents an inclined face or edge, 22. The arrangement is such that when the slips have been applied to the board body in the manner suggested above a rotation of the shafts, 11, projects the toes, 16, into the recesses, 21, the inclined faces, 17, of the toes coming against the inclined edges, 22, of the recesses. On account of the inclination of the faces at which the toes and the recesses, 21, engage each other, it will be understood that a certain wedging action takes place tending to hold the shaft in its locked position. The shafts, 1]., may be considered as locking shafts, each of which operates to lock the slips at one end of the board. In order to insure that no backward rotation of the'shafts may take place when the slips have been locked in, the aforesaid keepers, 19, are provided. The engagement which takes place between the ends of these keepers and the teeth, 18, evidently will effectually prevent any backward rotation of the shafts.

In order to provide for an inward adjustment of the collars, 15, on their shafts, the collars are preferably attached each by means of a set screw, 23, the point of the screw being received in a short longitudinal slot, 24, as shown at the left in Fig. 2, and the openings, 14, are made somewhat wider than the length of the collars so as to admit of the adjustment suggested, as will be readily understood.

It will be observed from inspection of Fig. 2 that the recesses, 21, are very shallow, so that ample material is left above them in which the thumb-tack, 25, may

, seat so as to hold the drawing-paper, a portion of which is indicated at 26. The outline of this sheet of drawingpaper is represented by the dotted line at 27 in Fig. 1. It will be observed that the corners of the drawing-paper lie over the slips where the thumb-tacks are applied.

In practice, the body of the drawing-board is formed of a hard, durable wood, while the slips, 8, are formed of a light wood, or soft material, in which the thumbtacks may be readily inserted. When the slips, 8 become worn from'constant use to such an extent that the ability to hold the tacks becomes impaired, they may be readily removed and replaced by perfect slips. In order to remove the slips, as suggested, it is only necessary to lay the board flat upon its face and rotate the shaft by means of a screw-driver, the collars being first released from the keepers, 19.

In addition to the function of the shafts, by virtue of which they operate as lock-shafts for the slips, attention is called to the fact that they operate as stiffeners or strong backs for the drawing-board; they tend to prevent warping of the board or the cleats in which they are received.

Having described my invention, what I claim and wish to secure by Letters Patent is:

1. A drawing-board having a plurality of removable slips mounted in the face thereof respectively at the points where the thumb-tacks are applied;

2. A drawing-board having removable triangular slips of a soft material mounted flush in the face thereof and adapted to receive the thumbtacks, and having means for retaining said slips therein.

3. A drawing-board having a plurality of recesses formed in the face thereof and located respectively at the corners thereof and removable slips received in said recesses. and a tongue-andgroove connection between said slips and the edges of said recesses.

+1. A drawingboard having a body with recesses formed in the face thereof, slips mounted in said recesses flush with the face of said body and presenting a continuous unbroken upper surface and means for locking said slips in said recesses from the under side.

5. A drawing-board having recesses in the face thereof constituting seats, removable slips adapted to be received in said seats, said slips having locking recesses in the under sides thereof, and :1 rotatable member mounted in said board and having means for engaging said'locking recesses to lock said slips against removal.

(3. A drawingboard having recesses formed in the upper face thereof constituting seats, slips mounted in said recesses and having locking recesses in the under faces thereof, transverse shafts rotatably mounted in said board, and having collars adapted to engage in said locking recesses. said shafts having heads disposed at the edge of said board, said first recesses having under-cut grooves formed at the edges thereof, said slips having tongues received in said grooves.

T. A drawing-board having recesses formed in the face thereof and constituting seats, slips received in said seats, and having locking recesses on the under faces thereof; transverse shafts having collars adapted to engage said locking recesses to lock said slips against withdrawal, and means for locking said shafts against rotation.

WILLIAM C. MCKENZIE.

Witnesses F. D. AMMEN, luVERARD B. MARSHALL. 

